Lock-switch sewing-machine.



L. E. TOPHAM.

LOCK STITCH SEWING MACHINE. APPLICATION men JULY23, 1914.

Patented July 11, 1916.

LAURENCE E. TOPHAM, 0F SWAMPSCOTT, MASSACHUSETTS, ASSIGNOR TO UNITED SHOE MACHINERY COMPANY, OF PATERSON, NEW JERSEY, A CORPORATION OF NEW JERSEY.

LOCK-STITCH SEWING-MACHINE.

' Specification of Letters Patent.

Patented July 11, 1916..

Original application filed May 20, 1912, Serial No. 698,458. Divided and this application filed July 23, 1914. Serial No. 852,775.

To all whom it may concern:

Be it known that I, LAURENCE E. Toi HAM, a citizen of the United States, residing at Swampscott, in the county of Essex and State of Massachusetts, have invented certain new and useful Improvements in Look Stitch Sewing-Machines; and I do hereby declare the following to be a full, clear, and

exact description of the invention, such as stationary bobbin case by means of a rotary loop-taker.

The object of the present invention is to provide a lock stitch sewing machine with a bobbin case which is rotatably supported by a rotary loop-taker, and has an improved detent for holding the bobbin case stationary as the loop-taker rotates.

With this object in view,the present inven tion consists in the improvement in look stitch sewing machines hereinafter described and particularly pointed out in the claims.

In the drawings which illustrate the preferred embodiment of the invention Figure 1 is an elevation taken partly in section, of the bobbin case, the loop-taker and its actuating mechanism, and Figs. 2 and 3 are sectional views taken on the line 22 of Fig. 1 and illustrate the bobbin case detent in different positions.

Referring to the drawings, the: loop of thread drawn out by the needle is cast around the bobbin case by means of a rotary loop-taker indicated generally by reference numeral 2. The loop-taker comprises an annular body portion 4 and an inwardly directed thread engaging beak 6 which is arranged to take the thread from the needle. The annular body portion 4 has at its lower end an inwardly projecting flange 8 which is engaged in an annular race-way formed between the body of the loop-taker support 10 and a plate 12 secured to the top of the support. The loop-taker makes three revolutions to each reciprocation of the needle and is continuously rotated in timed relation therewith by means of a bevel gear 14 which meshes with bevel gear teeth 16 cut in the periphery of the annular loop-taker body. The needle (not shown) is arranged to pass upward through the loop taker and draws down the thread loop which is entered by the beak 6. The loop-taker support 10 is arranged to be oscillated about a pivot 18 by means of a link 20, so that beak 6 will clear the needle during its idle revolutions. The above described parts are substantially the same, and operate in a manner similar to the corresponding parts illustrated and described in my co-pending application for sewing machines, Serial No. 621,286, filed April 15, 1911.

The bobbin case, indicated generally by reference numeral 34, is rotatably mounted within the annular loop-taker by means of an inwardly extending annular flange 30 lying in a plane atright angles to the axis of rotation of the loop-taker and received in a race-way 32 cut around the periphery of the bobbin case. The bobbin case comprises a discoidal one piece body 36. The body is cup-shaped, having a circular open-topped recess 60 in which the bobbin 62 is rotatably mounted on a central post 64 upon which it is retained by means of a latch 66. On the lower face of the body is a projection 38 in which is cut a slot 40. The sides of the slot 40 are plane and parallel'and the bottom is out on an arc of a circle.

A detent is provided for holding the bobbin case stationary as the loop-taker rotates. The detent comprises a plate 42 which is a substantially quadrantal sector. The edge of the plate 42 has the same radius of curvature as the bottom of the slot 40. A notch 44, which is somewhat deeper than the slot 40, is cut in the middle of the curved slotengaging edge of the plate 42 for a purpose hereinafter pointed out. The plate 42 is formed integral with a rock shaft 46 which is journaled in a bushed bearing 48 in the loop-taker support 10. The inner edge of the rock shaft 46 has a laterally extending arm 50 which bears a pin 52. The pin 52 is received in a cam path 54 in the gear wheel 14. The cam path 54 is so timed that the detent plate 42 is oscillated back and forth between the two positions shown in Figs. Q-andj 3 respectively, in timed relation to the rotary loop-taker. The loop-taker 2 rotates from left to right as viewed in Figs.

' in the position shown in Fig. 3. The beak 6 travels first from the left to the right in front'of the bobbin case and then from right to left 'behindthe bobbin case, as

viewed in Fig. 3, and spreads the loop of 'needle thread over the bobbin-case. The top upper leg of the loop is free to pass over the unobstructed upper face of the bobbin-case and the lower leg of the loop is drawn into v the notch M which occupies the position shown in Fig. 3; As the beak 6 continues to travel around behind the bobbin case, as

cviewed-injFigs. 2' and 3, the pin travels into a part of the cam path 54 nearer the axis of-thewheel ltand rocks the detent plate 42 to the left from the position shown in Fig; 3 to the position shown in Fig. 2. By the time the detent plateflQ has reached" the position "shown in Fig. 2 and the notch H has released the thread, the beak-6 will'havetr aveled completely' around the bobbin case so that the loop of needle thread can be pulled free from the bobbin case and against the work by the take-up'of the sewing machine. It will be noted that the detent plate 42 is always in engagement with the slot 40, so

1 that the bobbin case is always held against rotation with the loop-taker. The detent is positively oscillated, so that after the lower leg of the-thread loop is drawn into the notch 44 the thread is positively carried between the bobbin case and detent across the lowerface of the bobbin case the length of the slot 40. WVhile the'loop-taker as described above,

rotates continuously, it will be obvious that the detent mechanism would operate successfully to hold the bobbin case stationary if the loop-taker oscillated about its axis.

' The'expression rotary loop-taker, as used in the statement of invention; and in the claims, is intended to definea loop-taker Which rotates about an axis whether the rotary motion is continuous or oscillatory.

While the preferred embodiment of the present invention has been specifically illustrated and described, it is to be understood that the present invention is not limited to the details of construction illustrated and described, but may be embodied in other structures within the scope of the invention as defined by'the following claims 7 '1. A lock-stitch sewing machine, having,

in combination, a rotary loop-taker, a stationary bobbin ease supported by the looptaker and having a detent receiving slot in its face, and a movable detent slidingly engaging the slot and having a notch in its edge for engaging the needle-thread and carrying it longitudinally of the slot between the bobbin case and detent.-

2. A lockstimh sewing machine having, in combination, a rotary loop-taker, a stationary bobbincase supported by the looptaker and having a detent receiving slot in its face, a movable detent slidingly engaging the slot and-having provision for engaging the needle-thread, carrying it across the face of the bobbin case longitudinally of the slot and releasing it, and means for actuating the detent in timed relation with the loop-taker. '3. A lock-stitch sewing machine having, in combination, a rotary loop-taker having an annular body portion, a stationary discoidal slot. e

LAURENCE E. TOPHAM. Witnesses:

Gno'E. SrnBBINs, WILBUR B.'JOHNSON.

Copies of this patent may be obtained. for five cents each, by addressing the Commissioner of Patents,

7 Washington, D. G. 

